That's fanon, actually. It was how some people interpreted that flashback scene in Runner when the Wraith backed away from feeding on him, but Mallozzi (or one of them, anyway) said in one of the commentaries awhile back that they'd never meant to imply that he couldn't be fed on, just that the Wraith thought he looked strong and decided to make him a Runner rather than feeding on him. I wish I could point you to a specific link, but I can't remember where exactly it was -- just that the show-runners have gone on record as saying that he can be fed on just like anyone else.